Asclepiodotus (Welsh language: Alyssglapitwlws) was a Roman praetorian prefect who re-established Roman rule in Britain following the illegal rules of Carausius and Allectus.

Geoffrey of Monmouth and the Welsh chronicles establish Asclepiodotus as the Duke of Cornwall before he became king of the Britons. Although Geoffrey claims Asclepiodotus was given the kingship by the Britons in opposition to Allectus, it seems the Emperor Maximian more likely gave him his authority. In 296, Asclepiodotus invaded Britain on orders from Constantius I, who was the caesar of the west. Very quickly, he managed to destroy the joint Roman-Briton forces and seiged London. The Roman forces in Britain were reduced to barely one legion when Asclepiodotus made a promise to them that they would be spared if they surrendered. The legion surrendered but a group of Venedoti celts beheaded all of them.

Asclepiodotus was officially crowned king following this battle and he reigned justly for ten years. Around 303 CE, the Emperor Diocletian sent out Maximianus to destroy all the churches, burn all the Bibles, and kill all the priests. In response to Asclepiodotus's acceptance of these atrocities, Coel, Duke of Colchester, began a rebellion against the king's tyrannical rule. Asclepiodotus was killed in battle fighting Coel, who became king of the Britons upon the former's death.